Volume Type Scheduler

To create a basic volume-type aware scheduler and all required infrastructure for reporting volume capabilities from nova-volume nodes (pretty much reuse the existing infrastructure).
It should be able to find nodes best suited for hosting volume of particular type (with some special properties).

We're going to push this to G2 to allow some more time/thought on the implementation and review. There's some opportunity here to utilize OSLO a bit more, and actually some changes that we've made here we may like to see pulled up in to OSLO and used by other projects.